The present invention relates to a solid state image pickup device in which the charges obtained in a photoelectric converter portion are transferred to a charge/voltage converter portion by predetermined driving pulses, and converted into required voltages to output.
In general, a solid state image pickup device is provided with a row or a plurality of rows of photoelectric converter portions and the charges obtained there are transferred to a charge/voltage converter portion for outputting a voltage signal thus obtained.
The charges are transferred using predetermined clock pulses. The clock pulses necessary for transferring the charges are listed as follows;
(1) A readout-gate-pulse from the photoelectric converter portion to a CCD (Charge Coupled Device) register, (2) A transfer pulse for transferring the charges obtained in the photoelectric-converter portion to the charge/voltage converter portion, (3) A transfer pulse in the last stage right before the charge/voltage converter portion, and (4) A reset pulse in the charge/voltage converter portion.
In a case, these clock pulses are supplied from an external apparatus, or in another case that only a certain kind of clock pulse is supplied from an external apparatus and the other clock pulses necessary for transferring the charges are generated by a timing generator and a driver inside the device.
However, in a solid state image pickup device as mentioned in the above, in a case where a user wants to drive the device at a different timing within the conditions allowed to use the solid state sensor device, or in another case where a user wants to use only a part of the plurality of photoelectric converter portions, sometimes the revision of an external circuit is needed by supplying clock pulses thereto, or an influence of a signal supplied from an external apparatus may exert on the clock pulses generated by an internal timing generator.
Besides, in the case where a user wants to use only a part of the plurality of photoelectric converter portions, the clock pulses from an external apparatus intended to supply only to a part of the portions can be delivered to all pixels in the photoelectric converter portion, and in particular in a case where high speed transfer is needed, since the load capacity of the transfer pulses becomes as much as the load capacity for all CCD registers, a physical restriction can be produced.